1. Field of the Invention
The present invention relates to stroke discrimination of a single-cylinder internal combustion engine.
2. Description of the Related Art
An apparatus for discriminating the stroke of internal combustion engines is disclosed in Japanese Patent Kokai No. 61-89959. The apparatus discriminates engine strokes using two detection signals transmitted by two crank angle sensors, respectively, which are provided near the crankshaft.
Conventional apparatuses require two crank angle sensors and there has been no other choice but to use a complicated structure to utilize the two sensors. In addition, two detection signals are required to discriminate engine strokes, and therefore the apparatuses present a drawback in that it takes a long processing time to discriminate the engine stroke.
The present invention was developed in view of the aforementioned problems in the prior art. It is therefore an object of the present invention to provide an apparatus having a simple configuration for discriminating the stroke of an internal combustion engine to determine the stroke of the internal combustion engine.
A stroke discriminator of an internal combustion engine according to the present invention comprises a rotor operatively associated with a crankshaft of a single cylinder internal combustion engine and provided with a plurality of detected elements thereon. The stroke discriminator also comprises detector means for transmitting a detection signal every time said detected elements pass nearby and discriminator means for determining a stroke of the internal combustion engine in accordance with a difference in time between a transmission of a previous detection signal and a transmission of a current detection signal. The stroke discriminator is characterized in that an outer periphery of said rotor has a detected-element region having said plurality of detected elements formed thereon at equal angle intervals in a direction of rotation and a region which does not have detected elements formed thereon. The stroke discriminator is also characterized in that said region without the elements has an angle interval greater than said equal angle interval, and said region without the elements is provided on said rotor so as to pass near said detector means when a piston of said internal combustion engine travels from the top dead center to the bottom dead center.
That is, according to the feature of the present invention, it is possible to identify the stroke of an internal combustion engine in a short time with a simple configuration.